Republican U.S. Rep. Connie Mack announced his U.S. Senate bid in a Nov. 28, 2011, interview with Sean Hannity on Fox News.

Mack -- with some help from Hannity -- tried to sell the message that the incumbent, Democratic Sen. Bill Nelson, moves in lockstep with President Barack Obama.

"I am going to run for the United States Senate because frankly, I think the people of Florida have had enough," Mack said. "They've had enough of every time they turn around, Sen. Nelson is supporting and helping Barack Obama with Barack Obama's agenda of more government whether it's helping him with Obamacare. You know, Sen. Nelson was there right by Obama's side. Whether it was the stimulus, again, Sen. Nelson was right by Obama's side to make sure that was passed. Whether it was trillions of dollars in more spending, more tax increases, you name it on down the line. Sen. Nelson has been one of Barack Obama's go-to guys in the Senate."

This web ad, paid for by Friends of Connie Mack at lockstepliberals.com, shows Obama and Nelson embracing. And Hannity suggested that Nelson, first elected in 2000, is also in lockstep with his party:

"Well, the other thing is he's voted with the Democrats in Congress nearly 95 percent of the time. I was looking up his record," Hannity said. "He praised Obama during the last election. Now he doesn't want to be seen with Obama, which is pretty interesting. And I think the thing that has resonated nationally ..."

Here, we decided to check Hannity, since he offered the most precise measure of Nelson's partisan leanings -- that he "voted with the Democrats in Congress nearly 95 percent of the time." We couldn't reach Hannity and during the interview he didn't specify any timeline for Nelson's votes, so we focused on the most recent vote analyses from a few different organizations that compare Nelson's voting record with the rest of the Senate.

OpenCongress. Created by the Participatory Politics Foundation and the Sunlight Foundation, OpenCongress measures how often senators vote with their party, factoring in every single vote since the beginning of the current 112th session of Congress. According to OpenCongress, Nelson voted with his party on 190 out of 209 votes, a percentage of 90.9 percent.

While seemingly high, that voting record actually put him near the bottom of Democrats in the U.S. Senate -- ranking 39th out of 51. Why? Because the percentage itself is a poor indicator of partisanship, OpenCongress itself says. "Since the vast majority of the hundreds of votes factored in are routine in nature, the result is that even highly independent senators have a seemingly high score on voting with their party," the website says in a disclaimer. Relatively, then, Nelson ranks among more moderate Democrats.

U.S. Congress Votes Washington Post database. The Washington Post analysis measured 208 votes in the 112th Congress, finding that Nelson voted with his party 94 percent of the time. The database shows about 39 senators, Republicans and Democrats, voted with their party more often than Nelson (there are a lot of ties included).

National Journal ranking. The National Journal measures votes differently, only examining votes taken on key economic, social and foreign policy issues. The publication then assigns members a composite score and commensurate ranking. In 2010, Nelson ranked as the 42nd most liberal and 53rd most conservative senator, according to the Journal. The Journal placed Nelson in the "centrists" category.

CQ Vote Studies.Congressional Quarterly's analysis assigns members a score based on "party unity" -- or the frequency that someone votes with their party on occasions when a majority of Republicans oppose a majority of Democrats. If both parties supported a piece of legislation it wasn't included in the analysis -- in 2010, CQ analyzed 299 votes in the Senate. Nelson received an 89 percent in 2010. (To view historical data requires a subscription but CQ emailed us a chart showing Nelson's scores for a decade which ranged from 76 to 93 percent in the past decade. CQ told us that Nelson's score is 90 percent so far in 2011 as of 3 p.m. Nov. 29, 2011.)

Our ruling

Hannity said that Nelson "voted with the Democrats in Congress nearly 95 percent of the time." The Washington Post database shows Nelson voted with his party 94 percent of the time for the current session -- and OpenCongress shows a slightly lower figure at 90.9 percent with CQ not far behind at 89 percent.

But simply reporting the figure doesn't provide context.

Even highly independent senators have a seemingly high score when it comes to voting with their party, in large part because most votes are routine in nature. A more useful measure might be comparing the relative position of one senator to another, or comparing the position of all senators en masse.

That comparison shows that Nelson is much more of a moderate than Hannity's figure suggests.

Nelson is the 42nd most liberal senator out of 100, according to the National Journal, while OpenCongress says there are 38 more reliable Democratic votes. That's why we rate this claim Half True.

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